Gum Disease, Alzheimer's Disease May Be Linked

People with poor oral hygiene or gum disease may be at a greater risk of developing Alzheimer's disease, according to a study published online in the Journal of Alzheimer's Disease on May 10.

Researchers at The University of Central Lancashire (UCLan) School of Medicine and Dentistry in England led by Drs. StJohn Crean and Sim K. Singhrao examined brain tissue samples donated by 10 patients without dementia and 10 patients with dementia.They found gum disease bacteria lipopolysaccharides (the surface of the bacterium) in the sample from four of the people with dementia and none of the people who did not have dementia. Bacteria can enter the bloodstream through everyday activities such as eating, chewing and toothbrushing. Once in the bloodstream, the bacteria can be carried to other parts of the body.

The researchers hypothesized that when the bacteria reach the brain, they may trigger an immune system response (like they do in the mouth), killing brain cells.This immune response could be one mechanism that leads to changes in the brain, which is typical in Alzheimer's disease. It could play a role in causing symptoms such as confusion and deteriorating memory.

This new research indicates a possible association between gum disease and individuals who may be susceptible to developing Alzheimer's disease, if exposed to the appropriate trigger, said Dr. Crean, who is the dean at the School of Medicine and Dentistry. Research currently underway at UCLan is playing an active role in exploring this link, but it remains to be proven whether poor dental hygiene can lead to dementia in healthy people, which obviously could have significant implications for the population as a whole. It is also likely that these bacteria could make the existing disease condition worse.

This was a small study examining only brain tissue samples from only 20 people. Because of that, the association between Alzheimer's disease and gum disease in this study could have occurred by chance. It is also possible that people with Alzheimer's disease have worse oral hygiene than do people without dementia. Therefore, the bacteria in the brain tissue may be the result of Alzheimer's disease, not the cause. More research is needed to determine whether or not having gum disease increases the risk of developing Alzheimer's disease.